package org.brisling.common.util;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.Security;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;

public class EncrptUtil {
	
	
	      
	    //KeyGenerator 提供对称密钥生成器的功能，支持各种算法  
	    private KeyGenerator keygen;  
	    //SecretKey 负责保存对称密钥  
	    private SecretKey deskey;  
	    //Cipher负责完成加密或解密工作  
	    private Cipher c=null;  
	    //该字节数组负责保存加密的结果  
	    private byte[] cipherByte;  
	    
	    public EncrptUtil(){}
	      
	    @SuppressWarnings("restriction")
		public void initCipherAES() throws NoSuchAlgorithmException, NoSuchPaddingException{  
	        Security.addProvider(new com.sun.crypto.provider.SunJCE());  
	        //实例化支持DES算法的密钥生成器(算法名称命名需按规定，否则抛出异常)  
	        keygen = KeyGenerator.getInstance("AES");  
	        //生成密钥  
	        deskey = keygen.generateKey();  
	        //生成Cipher对象,指定其支持的DES算法  
	        c= Cipher.getInstance("AES");  
	    }  
	      
	    /** 
	     * 对字符串加密 
	     *  
	     * @param str 
	     * @return 
	     * @throws InvalidKeyException 
	     * @throws IllegalBlockSizeException 
	     * @throws BadPaddingException 
	     * @throws NoSuchPaddingException 
	     * @throws NoSuchAlgorithmException 
	     */  
	    public byte[] encrytor(String str) {  
	        // 根据密钥，对Cipher对象进行初始化，ENCRYPT_MODE表示加密模式 
	    	try{
	    		if(c==null)
	    			initCipherAES();
	    		c.init(Cipher.ENCRYPT_MODE, deskey);
	    		byte[] src = str.getBytes();  
	    		// 加密，结果保存进cipherByte  
	    		cipherByte = c.doFinal(src); 
	    	}catch(Exception e){
	    		e.printStackTrace();
	    	}
	          
	         
	        return cipherByte;  
	    }  
	  
	    /** 
	     * 对字符串解密 
	     *  
	     * @param buff 
	     * @return 
	     * @throws InvalidKeyException 
	     * @throws IllegalBlockSizeException 
	     * @throws BadPaddingException 
	     * @throws NoSuchPaddingException 
	     * @throws NoSuchAlgorithmException 
	     */  
	    public byte[] decryptor(byte[] buff)  {  
	        // 根据密钥，对Cipher对象进行初始化，DECRYPT_MODE表示加密模式 
	    	try{
	    	if(c==null)
	    		initCipherAES();
	        	c.init(Cipher.DECRYPT_MODE, deskey);  
	        	cipherByte = c.doFinal(buff);  
	    	}catch(Exception e){
	    		e.printStackTrace();
	    	}
	        return cipherByte;  
	    }

}
